rhOver: Determination of magnetic anisotropy and related properties for dysprosium(III) single-ion magnets by semiempirical approaches utilizing Hartree-Fock wave functions.

Dysprosium(III) ions are promising candidates for the design of single-ion magnets (SIMs) as they show an intrinsic strong magnetic anisotropy. However, time-demanding multireference methods are usually necessary to reproduce low-lying magnetic states. In this work, we present an improved wave function-based semiempirical ligand-field (LF) theory approach to obtain magnetochemical properties of dysprosium(III)-based SIMs. We reduce the computational effort by replacing the central dysprosium(III) ion with either yttrium(III) or lutetium(III), which allows to obtain a closed-shell wave function from Hartree-Fock calculations. The wave function is subsequently used to determine a so-called diamagnetic-electrostatic pseudo-potential (DEPP) of the compound, which in turn can be applied to LF theory to obtain magnetochemical properties. The presented approach is tested against ab initio CASSCF/RASSI-SO reference calculations and shows accurate prediction of magnetic anisotropy axes and a significant accuracy improvement as compared to point charge-based LFT methods. In addition, we also introduce an improved electrostatic (IES) approach, which applies the obtained DEPPs to a known electrostatic method introduced by Chilton et al. (Nat. Commun. 2013, 4, 2551) to obtain the direction of the main anisotropy axis in dysprosium(III)-based SIMs. © 2018 Wiley Periodicals, Inc.